J9382

ABSTRACT: δ-Stearolactone was prepared from oleic acid using concentrated sulfuric acid under various conditions in the presence of polar, nonparticipating solvents. δ-Stearolactone was formed in as high as 15:1 ratios over the thermodynamic product, γ-lactone, in the presence of methylene chloride, 100% wt/vol, at room temperature with two equivalents of sulfuric acid for 24 h. This procedure is applicable to other olefinic fatty acids such as estolides and fatty acid methyl esters. Temperature plays a role in the regioselectivity of the cyclization for δ-lactone, as lower temperatures (20°C) gave higher δ/γ ratios. At higher temperatures (50°C) in the presence of sulfuric acid and methylene chloride the yield of lactone was 75% but with a δ/γ ratio of only 0.3:1. Cyclization of oleic acid to lactone also occurred with other acids. Oleic acid underwent reaction with perchloric acid, one equivalent, in the absence of solvent at 50°C, which yielded δ-lactone in a modest yield with a 3.1 δ/γ ratio. The same temperature effect was observed with perchloric acid that was observed in the case of sulfuric acid. Because δ-stearolactone is much more reactive than the corresponding fatty acid, fatty acid ester, or γ-lactone, we believe that it will be a useful synthon for many new industrial products including new biodegradable detergents

A push–pull strategy to suppress stable fly (Diptera: Muscidae) attacks on pasture cattle via a coconut oil fatty acid repellent formulation and traps with \u3ci\u3em\u3c/i\u3e-cresol lures

BACKGROUND: Stable flies [Stomoxys calcitrans (L.)] are economically important pests of cattle and other livestock. As an alternative to conventional insecticides, we tested a push–pull management strategy using a coconut oil fatty acid repellent formulation and an attractant-added stable fly trap. RESULTS: In our field trials we found that weekly applications of a push–pull strategy can reduce stable fly populations on cattle as well as a standard insecticide (permethrin). We also found that the efficacy periods of the push–pull and permethrin treatments following on-animal application were equivalent. Traps with an attractant lure used as the pull component of the push–pull strategy captured sufficient numbers of stable flies to reduce on-animal numbers by an estimated 17–21%. CONCLUSIONS: This is the first proof-of-concept field trial demonstrating the effectiveness of a push–pull strategy using a coconut oil fatty acid-based repellent formulation and traps with an attractant lure to manage stable flies on pasture cattle. Also notable is that the push–pull strategy had an efficacy period equivalent to that of a standard, conventional insecticide under field conditions

Spatial repellency, antifeedant activity and toxicity of three medium chain fatty acids and their methyl esters of coconut fatty acid against stable flies

BACKGROUND: Stable flies are one of the most detrimental arthropod pests to livestock. With changing climates and agronomic practices, they expand their roles as pests and disease vectors as well. Their painful bites reduce livestock productivity, annoy companion animals, and interfere with human recreational activities. Current management technologies are unable to effectively control stable flies. The present study reports new results concerning the contact, spatial repellency, and toxicity of a bio-based product, coconut fatty acid and their methyl ester derivatives of free fatty acids of C8:0, C10:0 and C12:0 to stable flies. RESULTS: Three medium chain fatty acid methyl esters (C8:0 , C10:0 and C12:0 ) showed strong antifeedant activity against stable flies and their strengths were dose-dependent. Only the C8:0 acid, C8:0 - and C10:0 methyl esters elicited significant antennal responses. Laboratory single cage olfactometer bioassays revealed that coconut fatty acid and C8:0 methyl ester displayed active spatial repellency. All three methyl esters showed strong toxicity against stable flies. CONCLUSION: Antifeedant activity is the main method through which coconut fatty acid deters stable fly blood-feeding. The C8:0, C10:0 and C12:0 methyl esters act not only as strong antifeedants, but also possess strong toxicity against stable fly adults. Limited spatial repellency was observed from coconut fatty acid and C8:0 methyl ester

Spatial repellency, antifeedant activity and toxicity of three medium chain fatty acids and their methyl esters of coconut fatty acid against stable flies

BACKGROUND: Stable flies are one of the most detrimental arthropod pests to livestock. With changing climates and agronomic practices, they expand their roles as pests and disease vectors as well. Their painful bites reduce livestock productivity, annoy companion animals, and interfere with human recreational activities. Current management technologies are unable to effectively control stable flies. The present study reports new results concerning the contact, spatial repellency, and toxicity of a bio-based product, coconut fatty acid and their methyl ester derivatives of free fatty acids of C8:0, C10:0 and C12:0 to stable flies. RESULTS: Three medium chain fatty acid methyl esters (C8:0 , C10:0 and C12:0 ) showed strong antifeedant activity against stable flies and their strengths were dose-dependent. Only the C8:0 acid, C8:0 - and C10:0 methyl esters elicited significant antennal responses. Laboratory single cage olfactometer bioassays revealed that coconut fatty acid and C8:0 methyl ester displayed active spatial repellency. All three methyl esters showed strong toxicity against stable flies. CONCLUSION: Antifeedant activity is the main method through which coconut fatty acid deters stable fly blood-feeding. The C8:0, C10:0 and C12:0 methyl esters act not only as strong antifeedants, but also possess strong toxicity against stable fly adults. Limited spatial repellency was observed from coconut fatty acid and C8:0 methyl ester

Better than DEET Repellent Compounds Derived from Coconut Oil

Hematophagous arthropods are capable of transmitting human and animal pathogens worldwide. Vector-borne diseases account for 17% of all infectious diseases resulting in 700,000 human deaths annually. Repellents are a primary tool for reducing the impact of biting arthropods on humans and animals. N,N-Diethyl-meta-toluamide (DEET), the most effective and long-lasting repellent currently available commercially, has long been considered the gold standard in insect repellents, but with reported human health issues, particularly for infants and pregnant women. In the present study, we report fatty acids derived from coconut oil which are novel, inexpensive and highly efficacious repellant compounds. These coconut fatty acids are active against a broad array of blood-sucking arthropods including biting flies, ticks, bed bugs and mosquitoes. The medium-chain length fatty acids from C8:0 to C12:0 were found to exhibit the predominant repellent activity. In laboratory bioassays, these fatty acids repelled biting flies and bed bugs for two weeks after application, and ticks for one week. Repellency was stronger and with longer residual activity than that of DEET. In addition, repellency was also found against mosquitoes. An aqueous starch-based formulation containing natural coconut fatty acids was also prepared and shown to protect pastured cattle from biting flies up to 96-hours in the hot summer, which, to our knowledge, is the longest protection provided by a natural repellent product studied to date